diff --git a/Library/Homebrew/readall.rb b/Library/Homebrew/readall.rb
index fb6fcac8a7..c1a79ab702 100644
--- a/Library/Homebrew/readall.rb
+++ b/Library/Homebrew/readall.rb
@@ -80,7 +80,7 @@ module Readall
       # Ignore unnecessary warning about named capture conflicts.
       # See https://bugs.ruby-lang.org/issues/12359.
       messages = messages.lines
-                         .reject { |line| line.include?("named capture conflicts a local variable") }
+                         .grep_v(/named capture conflicts a local variable/)
                          .join
 
       $stderr.print messages